A menhir (from Brittonic languages: maen or men, "stone" and hir or hîr, "long"), standing stone, orthostat, or lith is a large upright stone, emplaced in the ground by humans, typically dating from the European middle Bronze Age. They can be found individually as monoliths, or as part of a group of similar stones. Menhirs' size can vary considerably, but they often taper toward the top.
They are widely distributed across Europe, Africa and Asia, but are most numerous in Western Europe; particularly in Ireland, Great Britain, and Brittany, where there are about 50,000 examples, and northwestern France, where there are some 1,200 further examples. Standing stones are usually difficult to date. They were constructed during many different periods across prehistory as part of the larger megalithic cultures in Europe and near areas.
Some menhirs stand next to buildings that have an early or current religious significance. One example is the South Zeal Menhir in Devon, which formed the basis for a 12th-century monastery built by lay monks. The monastery later became the Oxenham Arms hotel, at South Zeal, and the standing stone remains in place in the snug bar at the hotel.
Where menhirs appear in groups, often in a circular, oval, henge or horseshoe formation, they are sometimes called megalithic monuments. These are sites of ancient religious ceremonies, sometimes containing burial chambers. The exact function of menhirs has provoked more debate than practically any other issue in European prehistory. Over the centuries, they have variously been thought to have been used by druids for human sacrifice, used as territorial markers, or elements of a complex ideological system, used as mnemonic systems for oral cultures, or functioning as early calendars. Until the nineteenth century, antiquarians did not have substantial knowledge of prehistory, and their only reference points were provided by classical literature. The developments of radiocarbon dating and dendrochronology have significantly advanced scientific knowledge in this area.